The present invention relates to data center infrastructure, and more particularly, this invention relates to supporting Storage Area Network (SAN) traffic over logical overlay networks and systems thereof.
Network virtualization is an emerging data center and cloud computing trend which aims to virtualize a network as seen by end stations in a way that greatly simplifies network provisioning in multi-tenant environments, as well as traditional environments. One of the more common techniques of achieving network virtualization is to use network overlays, where tunnels are established between servers, edge network switches, and gateways to which end stations connect. The tunnel is actually implemented by encapsulating packets transmitted by a source end station into an overlay header that transports the packet from the source switch to a target switch in user datagram protocol (UDP) transport via an internet protocol (IP)-based network. The overlay header includes an identifier (ID) that uniquely identifies the virtual network. The target switch strips off the overlay header encapsulation, UDP transport header, and IP header, and delivers the original packet to the destination end station. In addition to this tunneling mechanism, the edge switches participate in an address discovery protocol, which may be learning/flooding based, or lookup-based.
Overlay networks typically utilize an overlay-enabling technology, such as Virtual eXtensible Local Area Network (VXLAN), Locator/ID Separation Protocol (LISP), Overlay Transport Virtualization (OTV), Network Virtualization using Generic Routing Encapsulation (NVGRE), etc. Regardless of the overlay network supporting protocol, an overlay network connects geographically separated Layer-2 (L2) networks using L2 over Layer-3 (L3) tunnels. L2 packets originated by a virtual machine (VM) in an overlay network capable server and destined to another VM or group of VMs in same overlay network, but located in another physical location (such as on a different physical server) are carried over L3 tunnels, bypassing the L2 infrastructure.
Overlay networks allow stretching of VM mobility across L2 domains for VMs running Enterprise applications (typically built on top of IP over Ethernet). However, none of these technologies directly provide the benefits of overlay network usage to VMs exchanging SAN traffic, such as Fibre Channel over Ethernet (FCoE) traffic, Small Computer System Interface (SCSI), etc. For example, in conventional systems, flows of SAN traffic through the underlying network are separated from the flows of Enterprise Ethernet traffic thereby preventing the SAN traffic from taking advantage of the overlay networks. Therefore, it would be beneficial to have an overlay network which is capable of providing similar capabilities to SAN traffic as it does to IP traffic.